Conventional shortening compositions comprise a mixture of triglyceride materials which are respectively, liquids and solids at room temperature. Typically, the liquid triglyceride comprises about 85% of the shortening composition and the solid triglyceride about 15%. The compositions are prepared by hydrogenating a liquid triglyceride to the extent necessary to form the required amount of solid triglyceride within the mixture, or by hydrogenating a fraction of triglyceride to a high degree (Iodine Value from 0 to about 20) to form a high melting solid, and then blending this with a liquid oil to form the solid shortening. In either case, the solid component traps relatively large amounts of the liquid component within its crystal structure, thereby forming a solid shortening, notwithstanding the fact that the amount of solid triglyceride in the shortening composition is relatively small. See U.S. Pat. No. 3,706,578, Bence, issued Dec. 19, 1972.
In recent years considerable attention has been focused on the amount of triglyceride fat in the diet from the standpoint of health concerns about obesity and hypercholesterolemia. Numerous patents have been directed to providing materials which have the physical and gustatory characteristics of triglyceride fats, but which are absorbed to a low extent or not at all by the body. There materials are referred to variously as noncaloric fats, pseudofats, nondigestible fats and fat substitutes. Patents pertaining to such materials include U.S. Pat. Nos. 4,582,927, Fulcher, issued Apr. 15, 1986, (fatty esters of malonic acid); 4,582,714, Volpenhein, issued Apr. 15, 1986, (alpha acetylated triglycerides); and 3,579,548, Whyte, issued May 18, 1981, (triglycerides of alpha-branched chain carboxylic acids.
One particular type of compound which has achieved considerable attention as a nondigestible fat is sucrose polyester (i.e., esterified with a fatty acid). U.S. Pat. Nos. 3,600,186, Mattson, issued Aug. 17, 1971; 4,368,213, Hollenbach et al. issued Jan. 11, 1983; and 4,461,782, Robbins et al. issued July 24, 1984 describe the use of this material as a nondigestible fat in a variety of food compositions.
A problem associated with use of liquid nondigestible fats, i.e., those having a melting point below body temperature (about 37.degree. C.), is an undesired "laxative" effect, which is manifested in leakage of the liquid nondigestible fat through the anal sphincter. U.S. Pat. No. 4,005,195, Jandacek, issued Jan. 25, 1977, discloses the combining of higher melting fatty materials such as solid triglycerides and solid sucrose polyesters with the liquid sucrose polyesters in order to avoid the laxative effect.
An object of the present invention is to provide solid shortening in which the solid fat component is a nondigestible fat material which is highly effective in holding relatively large amounts of oil within its crystal structure.
Another object of the present invention is to provide solid shortening compositions in which both the oil component and the solid component are nondigestible and which do not have the anal leakage problem associated with nondigestible edible oils (i.e., those nondigestible edible oils which have a melting point below body temperature, which is about 37.degree. C.).
Another objective of the present invention is to provide food products which contain nondigestible edible oils but which do not have the anal leakage problem associated with such oils.
For purposes of describing this invention, the term "non-digestible" shall mean being absorbable to an extent of 70% or less (and especially 20% or less) by the human body through its digestive system.